Shock waves in sprays: numerical study of secondary atomization and experimental comparison

Abstract

International audienceNumerical modeling of the interaction between a cloud of water droplets and a planar shock wave is compared with experimental data. The mathematical model relies on an Eulerian description of the dispersed phase with the assumption of dilute flows. It is shown that the secondary atomization of the droplets strongly influences the structure of both the shock wave and the induced flow. After shock loading, the individual liquid components generate daughter droplets, and the overall interphase surface per unit volume undergoes strong variations which modify the pressure relaxation process towards a dynamic and thermal equilibrium state. The experimental data enable one to determine the best analytical formulation of the droplet number production rate. Models of droplet number production rate are compared in order to highlight this feature. The model based on the assumption of linear variation of droplet diameter with time gives the best agreement between the numerical results and the experimental data

Numerical analysis of the mean structure of gaseous detonation with dilute water spray

“…The convective heat flux is calculated using the Ranz-Marshall equation (Ranz & Marshall 1952). The droplet break-up occurs under the assumption that the droplet diameter decreases linearly during the break-up process (Chauvin et al 2016). It is a phenomenological model based on the critical Weber number (We c ) and the non-dimensional total break-up time which are modelled by Brodkey (1967) and Pilch & Erdman (1987), respectively.…”

Investigation of mechanisms leading to water drop breakup at Mach 4.4 and Weber numbers above 105

“…The breakup of liquid sprays exposed to a supersonic flow occurs in many industrial or research applications, such as propulsion (diesel engines [1], rotating detonation engines [2]), blast mitigation [3], and nuclear reactor safety [4]. Due to its importance, abundant work has been done to describe and understand the atomisation process, both experimentally [3] and numerically [5,6]. The usual macroscopic models describing fluid-spray interaction rely on coupling terms driving the mass, momentum and energy exchange between the liquid and gaseous phase [7].…”

“…The usual macroscopic models describing fluid-spray interaction rely on coupling terms driving the mass, momentum and energy exchange between the liquid and gaseous phase [7]. These coupling terms are directly related to the drop deformation and fragmentation (or breakup), which dramatically affect the exchange surface between both phases [5,8].…”

A model and numerical method for compressible flows with capillary effects

“…In some cases, this phenomenon causes damages as for example when droplets are impacting aircrafts in supersonic flight causing erosion of its surface (Engel [8], Joseph et al [23], Igra and Takayama [20,21]). Studying of droplets behavior in a high speed flow may also be encountered when security issues are considered as, for example, for shock wave attenuation (Chauvin et al [4,5]). Other applications can be found in explosive science or in combustion systems where a liquid jet is atomized (Welch and Boyle [52], Meng and Colonius [33], Devassy et al [7]).…”